Fix case where nat_gateway_enabled is false (#50)

examples/complete/main.tf

@@ -3,8 +3,9 @@ provider "aws" {
 }
 
 locals {
-  public_cidr_block  = cidrsubnet(var.cidr_block, 1, 0)
-  private_cidr_block = cidrsubnet(var.cidr_block, 1, 1)
+  public_cidr_block      = cidrsubnet(var.cidr_block, 2, 0)
+  public_only_cidr_block = cidrsubnet(var.cidr_block, 2, 1)
+  private_cidr_block     = cidrsubnet(var.cidr_block, 2, 2)
 }
 
 module "vpc" {
@@ -30,6 +31,20 @@ module "public_subnets" {
   context = module.this.context
 }
 
+module "public_only_subnets" {
+  source = "../../"
+
+  enabled             = var.enabled
+  availability_zones  = var.availability_zones
+  vpc_id              = module.vpc.vpc_id
+  cidr_block          = local.public_only_cidr_block
+  type                = "public"
+  igw_id              = module.vpc.igw_id
+  nat_gateway_enabled = false
+
+  context = module.this.context
+}
+
 module "private_subnets" {
   source = "../../"
 

examples/complete/outputs.tf

@@ -22,6 +22,10 @@ output "public_az_ngw_ids" {
   value = module.public_subnets.az_ngw_ids
 }
 
+output "public_only_az_ngw_ids" {
+  value = module.public_only_subnets.az_ngw_ids
+}
+
 output "private_az_route_table_ids" {
   value = module.private_subnets.az_route_table_ids
 }

main.tf

@@ -9,7 +9,7 @@ locals {
     subnet_id      = local.public_enabled ? aws_subnet.public[az].id : aws_subnet.private[az].id
     subnet_arn     = local.public_enabled ? aws_subnet.public[az].arn : aws_subnet.private[az].arn
     route_table_id = local.public_enabled ? aws_route_table.public[az].id : aws_route_table.private[az].id
-    ngw_id         = local.public_enabled ? aws_nat_gateway.public[az].id : null
+    ngw_id         = local.public_enabled && var.nat_gateway_enabled ? aws_nat_gateway.public[az].id : null
     }
   }
 }

test/src/examples_complete_test.go

@@ -16,6 +16,17 @@ func getKeys(m map[string]string) []string {
 	return keys
 }
 
+// Get values of a map in the same order that getKeys gets the keys of the map,
+// which is lexicographically sored by keys.
+func getValues(m map[string]string) []string {
+	values := make([]string, 0, len(m))
+	keys := getKeys(m)
+	for _, k := range keys {
+		values = append(values, m[k])
+	}
+	return values
+}
+
 func assertValueStartsWith(t *testing.T, m map[string]string, rx interface{}) {
 	for _, v := range m {
 		assert.Regexp(t, rx, v)
@@ -78,18 +89,23 @@ func TestExamplesComplete(t *testing.T) {
 	// Run `terraform output` to get the value of an output variable
 	publicNATGateWayIds := terraform.OutputMap(t, terraformOptions, "public_az_ngw_ids")
 	// Run `terraform output` to get the value of an output variable
+	publicOnlyNATGateWayIds := terraform.OutputMap(t, terraformOptions, "public_only_az_ngw_ids")
+	// Run `terraform output` to get the value of an output variable
 	publicRouteTableIds := terraform.OutputMap(t, terraformOptions, "public_az_route_table_ids")
 	// Run `terraform output` to get the value of an output variable
 	publicSubnetIds := terraform.OutputMap(t, terraformOptions, "public_az_subnet_ids")
 
 	expectedAZs := []string{"us-east-2a", "us-east-2b", "us-east-2c"}
+	expectedNulls := []string{"<nil>", "<nil>", "<nil>"}
 	// Verify we're getting back the outputs we expect
 	assert.Equal(t, expectedAZs, getKeys(privateSubnetIds))
 	assertValueStartsWith(t, privateSubnetIds, "^subnet-.*")
 	assert.Equal(t, expectedAZs, getKeys(privateRouteTableIds))
 	assertValueStartsWith(t, privateRouteTableIds, "^rtb-.*")
 	assert.Equal(t, expectedAZs, getKeys(publicNATGateWayIds))
 	assertValueStartsWith(t, publicNATGateWayIds, "^nat-.*")
+	assert.Equal(t, expectedAZs, getKeys(publicOnlyNATGateWayIds))
+	assert.Equal(t, expectedNulls, getValues(publicOnlyNATGateWayIds))
 	assert.Equal(t, expectedAZs, getKeys(publicRouteTableIds))
 	assertValueStartsWith(t, publicRouteTableIds, "^rtb-.*")
 	assert.Equal(t, expectedAZs, getKeys(publicSubnetIds))